The mean-field state observability assumption of Assumption REF  is the standard observation channel considered in works on mean-field games, see e.g. [1]} and the references therein. The observation channel of Assumption REF  can be motivated using the discussion above; it serves to lessen the computational burden at a given learning agent in a partially observed \(N\) -player mean-field game and, as we discuss in Section , may be a more appropriate modelling assumption in some applications.
